Analysis of fluoride and its remediation in groundwater of the rural areas of rajpura tehsil patiala punjab

Abstract

Groundwater is an important source of water supply throughout the world. The regions that are vulnerable to unreasonable withdrawal, generally lead to deficiency of groundwater. In our study, Bryophyllum pinnatum (B. pinnatum) raw biochar and activated biochar doped with aluminum were prepared from the leaves of the B. pinnatum plant. The removal efficiency of raw/pristine biochar (RB) and B. pinnatum-activated biochar (BAB) was investigated by treating both biochars with fluoride-contaminated water. The biochar was characterized using FTIR, FESEM-EDX, XRD, BET, and pHpzc techniques, which showed that the positive charges and adsorption sites were created due to the effective loading of the metal hydroxide on the biochar surface during BAB formation which played a significant role in defluoridation. Batch tests were carried out to investigate the effect of different factors on the percentage of fluoride removal. The optimized reaction conditions were obtained from the results at 10 mg L-1 of fluoride, 120 mins of contact time, pH = 6.0, and 1.0 g of dosage. Kinetic and isotherm models were also applied to evaluate the mode of action and mechanistic approach. The results revealed that BAB exhibited a higher fluoride removal efficiency of 92% compared to RB and followed the pseudo-2nd-order model and Langmuir model showing chemisorption and monolayer type of adsorption, respectively. The effect of co-existing ions was also investigated showing the carbonate ions showed maximum interference followed by sulfate, chloride, and nitrate ions, respectively. The cycle and regeneration studies showed the efficacy of the catalyst even after multiple cycles. The mechanism was also proposed by the results showing that the fluoride adsorption on BAB includes a combination of electrostatic interaction, H-bonding, surface adsorption, ion/ligand exchange, and inner sphere complexation of metal fluoride. Furthermore, the synthesis of Portulaca grandiflora (P. grandiflora) activated biochar (PAB) was obtained through the pyrolysis